Stimuli-Responsive Aqueous Micelles from an ABC Metallo-Supramolecular Triblock Copolymer

A metallo-supramolecular ABC triblock copolymer containing a bis(2,2‘:6‘,2‘ ‘-terpyridine)ruthenium(II) complex as a supramolecular connection between the constituting poly(styrene)-block-poly(2-vinylpyridine) diblock and poly(ethylene oxide) block (PS32-b-P2VP13-[Ru]-PEO70) has been prepared. This copolymer was further utilized in order to prepare aqueous micelles consisting of a PS core, a pH-sensitive P2VP shell, and a PEO corona. The accordingly formed micelles have been characterized by a combination of dynamic light scattering, transmission electron microscopy, and atomic force microscopy. Spherical micelles and a minor fraction of bigger aggregates were observed by these three independent techniques. The pH sensitivity of the P2VP shell could be demonstrated and the reversibility of the metallo-supramolecular complex investigated utilizing a strong competitive ligand.